Light scattering parameters will be obtained in phenomenological studies on normal and cataractous human lenses in in vivo examinations. Existing slit-lamp and ocular scattering apparatus will be modified to obtain scattering intensities in VV, VH, HH, and HV polarization modes. These parameters will be used for classification purposes as well as for observing cataract development. The transparency of the lens depends on short range order in the spatial distribution of scattering particle. To gain information on the spatial distribution, the supramolecular self and hetero aggregate structure of crystallins will be studied and the interaction forces operating among them. Refractive index gradient, second virial coefficient of light scattering on dilute solutions will be done as a function of pH, temperature, ionic strength and other environmental factors to yield such information. The contribution of cytoskeletal bodies to turbidity through optical anistropy fluctuation will be assessed by studying the birefringence and dichroism of the constituent molecules and in their self and hetero-aggregation states. Transparency of the lens also depends on the proper hydration and svneresis or swelling changes of hydration. Consequently, the role the different lens constituents (crystallins, cytoskeletal bodies) etc. play in the distribution of bound and free water in the lens will be studied by differential scanning calorimetry, thermogravimetric analysis, high vacuum water vapor sorption and the infra red spectroscopy of the sorption process. Finally, the hydration and structure of adjacent tissues such as, lens capsule, cornea and vitreous will be studied as they may be affected by cataractogenesis.